The present invention relates in general to methods and apparatuses for monitoring signals from and injecting signals to functional electrical circuitry, and, in particular to a new and useful method and apparatus of achieving these functions without contacting the electrical circuitry. For this purpose, the present invention utilizes laser-induced photoionization which creates plasma volumes that are utilized for monitoring and injecting the signals.
Mechanical pin contact electrical testers have been used for many years to monitor signals from and inject signals to electrical circuitry. The testers are brought into contact with printed wiring boards (PWV) and thus make physical contact with the various conductive connections of the electrical circuitry connected to the wiring boards. The simultaneous reduction of printed wiring board features and the utilization of a multitude of imbedded signal layers has rendered the use of mechanical electrical testers obsolete.
Fragile, "one-chance" connectors on high density input/output (I/O) boards require electrical testing of PWB's without actually contacting the connectors.
Non-contact technology is not currently available however, to achieve this function.
Extremely expensive functional and in-circuit testing equipment is, however, currently available, for example from Digital Equipment Corporation (DEC). Without non-contact testing (NCT) methodology, it is not practical to utilize this equipment on fragile and complex circuitry.